Art of pulverizing mineral substances or aggregates



Patented Aug. 13, 1935 UNITED STATES PATENT OFFICE ART OF PULVERIZINGLHNERAL SUBSTANCES OR AGGREGATES Reginald s. Dean, Washington, D. 0..and John Gross, Salt Lake City, Utah No Drawing.

Application February 14, 1931, Serial No. 515,890

2 Claims. (01. ass-94) The object of this invention is to reduce certainmineral substances or aggregates to a finely divided condition for anypurpose whatever but reduction of mineral substances or aggregates to afinely divided condition is accomplished by the application of forcesapplied externally such as in crushing rolls stamp mills, ball mills orsimilar devices. In these devices the energy input is inefficiently usedin producing fine particles. Our invention makes use of forces exertedby a controlled expansion of a substance existing or introduced into thepores or structure of the mineral substance or aggregate and is based inpart on the discovery that many mineral substances are more porous orpermeable to liquids than heretofore supposed. I This invention differsfrom the method sometimes used to break apart large pieces of rock byfreezing water in the crevices of the rock since it is applicable torocks with a different order of openings and is controlled so that itmay be made to take place suddenly. The same objection of lack ofcontrol applies to the very old art of heat chipping as applied bysavages to the forming of flint rocks or to various processes which havebeen proposed which involve sudden heating or cooling of rocks. In allof these cases only the surface may be strained sufficiently to break.

We are also aware that a number of processes have been patented but notgreatly usedin the art whereby the crevices existing in rocks orminerals or mineral aggregates are subjected to widening by means ofcorrosive agents or by means of introducing into such crevices solutionswhich give off a gas such as hydrogen peroxide. We are also aware thatminerals having water in their constitution such as vermiculite havebeen disintegrated by heating and that mineral aggregates have been tosome extent disintegrated by the repeated application of a vacuum. Weare also aware that materials have been pulverized by the suddenexpansion of a liquid placed in contact with them when heated in aconfined space.

We are also aware that substances have been disintegrated by confiningthem in a closed vessel with gaseous explosive agents.

We do not claim any of these processes but claim our process isdifferent therefrom in' that an explosive substance or one of itsconstituents is introduced into the pores or structure for minpores oron its surface.

. Percent zinc in material crushed thru 200 eral substance or aggregateby means of contact with a liquid or solution and the expansion within amineral aggregate may, accordingly, be so conirolled that one or moreconstituents of the aggregate ore pulverized more than others. 5

Further, our process does not require the confinement of the mineral oraggregate with the explosive or liquid.

The explosive, after being formed within the pores or structure of themineral is detonated by means of heat and shock. We do not claim any ofthese processes but claim that our process is generically differenttherefromin that the expansion within the substance is controllable sothat it may be made to take place suddenly. The results of such a suddenexpansion are as different from the heretofore practiced slow expansionsas is the burning of black powder in an open space to its explosion whenconfined or controlled. I

One form of our process is to treat the mineral substance or aggregateso that explosive material, such as silver acetylide is absorbed in itsThis may be accomplished by impregnating the mineral, for exam- 5 pleiron ore, with a solution of silver nitrate and subjecting it toacetylene gas. The explosive material is then caused to explode by heator percussion.

The pulverization produced by our method is notlimited to the tearingapart of the mineral or aggregate by the expansion of the materialwithin its pores or structure but additional pulverization is caused bythe impact of the partiticles with the sides of the container and witheach other.

Percent zinc before crushing 1.7

mesh by our process 10.9

This specification does not attempt to point out all the advantageswhich may be obtained by our invention nor the changes and substitutionsin form that may be made within the scope and spirit which are to belimited only by the appended cIaims.

We claim:

1. The process of pulverizing mineral substance which comprisesdispersing an explosive substance .in a liquid, soaking the mineralsubstance with the liquid to impregnate the mineral with the explosive,and detonating the explosive 6 substance.

2. The process of pulverizing mineral substances which comprisestreating the mineral substances with a plurality of chemical sub stancesto form an explosive from said substances within the pores and structureof the mineral and detonating said explosive,

JOHN GROSS. REGINALD s. DEAN.

